Injection ports are generally placed beneath the skin of a patient and have a variety of uses such as, for example, infusing medication, blood draws, and adjusting gastric bands. Since the early 1980s, adjustable gastric bands have provided an effective alternative to gastric bypass and other irreversible surgical weight loss treatments for the morbidly obese. A gastric band is generally wrapped around an upper portion of a patient's stomach such that a stoma is formed that restricts the passage of food from an upper portion to a lower portion of the stomach. When the gastric band is in place, and when the stoma is of the appropriate size, food held in the upper portion of the stomach provides a feeling of fullness that discourages overeating. However, initial maladjustment of the gastric band, or a change in the stomach over time, may lead to a stoma of inappropriate size that warrants adjusting the gastric band. For example, a patient may suffer vomiting attacks and discomfort if the stoma is too small to reasonably pass food. If the stoma is too large, and fails to slow food moving from the upper portion of the stomach, the gastric band may need to be tightened.
Gastric bands are generally adjusted with an inwardly directed inflatable balloon, similar to a blood pressure cuff, into which fluid, such as saline, is injected. Fluid and the like is frequently injected into the inflatable balloon with a fluid injection port that may be used to achieve a desired diameter. Because adjustable gastric bands generally remain in the patient for long periods of time, the fluid injection port is typically installed subcutaneously to avoid infection. Adjusting the amount of fluid in the adjustable gastric band is generally achieved by inserting a Huber needle through the skin into a silicon septum of the injection port. Once the needle is removed, the septum seals against the hole. A flexible conduit communicates between the injection port and the adjustable gastric band.
The silicone septum is generally partially self-healing such that multiple needle sticks may be performed before the septum becomes ineffective. This self-healing feature is generally achieved by applying an axial compressive load to the septum when it is assembled with the injection port. This axial force is generally achieved by sandwiching the septum between two adjacent pieces during assembly such that the septum will be compressively loaded throughout the duration of the procedure. This compressive load is often able to reseal imperfections in the septum caused by needle sticks.
Although the septum has the ability to self-heal after a number of needle sticks, this ability may begin to deteriorate as the septum is continually punctured due to, in part, the inability of the axial compressive load to reseal imperfections. Because injection ports are generally implantable, a gastric banding procedure or the like may have to be shortened or interrupted in order to remove and/or replace an injection port where a septum has become less effective or ineffective. Such a procedure may increase the costs to both the patient and the hospital and may pose a health risk to the patient if a surgical procedure is required to remove the injection port. Additionally, a gastric band or the like may be less effective if fluids or the like are able to diffuse or leak out as the septum loses integrity.
It would therefore be advantageous to provide a septum that has a longer useful life. It would be further advantageous to provide a septum that effectively reseals after a plurality of needle sticks and may be more easily assembled using conventional assembly mechanisms.